Re: ubitx spurs?

Curt
 

John

info appreciated.  I don't think you are likely using 50 volts audio -- maybe 50 mV ?  There may be more variation in the audio gain than RF perhaps.  I suggest you watch the output power as you adjust the audio, as producing an expected RF output tells us you are measuring spurs while simultaneously getting several watts of RF output. 

You didn't happen to say if this is v5 or a previous version?

I recognize that 12m spur being 5 MHz away -- mine has similar spurs almost equally below and above the carrier (one is a mixer spur, the other seems to be a signal passing through the mixer a second time (RF from PA leaking back into mixer input).  What you label as separation looks like you have subtracted the spur level from the main carrier?  By convention these are given as a negative value.  If you are outputting say 3 or more watts at 10m -- I really like your numbers -- they are 8 dB better than my v4.  Note your worst spurs are up there also, but yours are close to compliance - indeed if your rig is simultaneously outputting desired transmit power. 


The SSB spurs you are measuring tend to be a worse problem at the highest frequencies - I have non-compliant spurs on SSB only at 15, 12 and 10 meters. 

Also you need to seprately measure the worst harmonic.  Note these mostly impact bands at 20m and below, since the PA doesn't transmit as efficiently up above 10m where these spurs would land if they start at 18 MHz or higher. 

Be patient and you should get some good measurements. 

Curt

Join BITX20@groups.io to automatically receive all group messages.